Wall is wet but no leak???

Hello all,

Not exactly a DIY question as the work was done by skilled people but the situation has left all of us scratching our heads. Thought I'll turn to the collective experience of this forum for some ideas.

I had the central heating pipes chased into the living room wall and the radiator replaced. All was completed and tested by the plumbers before the chase was patched up and the wall plastered. All this was done about a couple of weeks ago and the plaster has fully dried since. Since that point up until last Saturday the CH system was drained and there was no central heating for various reasons. Come Saturday and I filled up the system to 2 bar (same as it was tested at) and restarted the CH. Soon after I spoted a few leaks on the wall along the pipe route (see pics).

Plumbers came back, broke into the chase where there were wet plaster patches but didn't find any leaking joints and the pipes were dry. One of the three "leak" locations didn't even have a joint there, only a bend! The pressure in the system didn't appear to have dropped either. So all of us are really baffled as to why there may be wet patches on the wall. Any ideas what it might be?

I should also mention that where the pipe drops down from above to the floor level, it tees off with one end going to the rad and the other end punching through the wall outside (for future extension). This punch out has not been filled in yet so potentially some rain water might have gotten in but wouldn't have thought it would go as far as the rad. Pipes were covered with denzo tape before putting the plaster on, is it possible that it could be the moisture from the tape getting to the surface of plaster?

What's the best way forward? But pack the denzo tape and patch up again or replace it with something else in the broken out sections?

Appreciate any thoughts.

Thanks!

If there are no leaks then the Denso tape is 'bleeding' through the plaster.

Andy

The wrong Denso tape has been used and is not suitible for heating pipes and is melting and bleeding through as @HERTS P&D.

https://www.denso-group.com/en/prod...astics/denso-tape-corrosion-prevention-tapes/

As others have said Denso will bleed when the pipes are hot, great stuff but shouldnt have been used in your situation

Understood. It does look like the denso tape is dry in those areas (perhaps it should be, not sure). And I've noticed that it's jot wrapped around the pipe like shown in your link JimCrow but rather folded around the pipe lenghtways.

Now that pretty much the whole pipe is covered in the wall, should I leave the tape as is and let it bleed through and dry out before painting? Or should I get them to re-wrap the whole pipe which is gonna be a major work? It does appear that the leaks were at the spots were the pipes were quite close to the surface, is there a chance it could still bleed in other places in the future?

Zinserr stain block on the walls where the pipes are should do you.

JimCrow said:

Zinserr stain block on the walls where the pipes are should do you.

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Thanks Jim, I wasn't aware of such product but it sounds promising. I guess that's the best I can do at the moment.

Thanks all for your input!

Bilis said:

Understood. It does look like the denso tape is dry in those areas (perhaps it should be, not sure). And I've noticed that it's jot wrapped around the pipe like shown in your link JimCrow but rather folded around the pipe lenghtways.

Now that pretty much the whole pipe is covered in the wall, should I leave the tape as is and let it bleed through and dry out before painting? Or should I get them to re-wrap the whole pipe which is gonna be a major work? It does appear that the leaks were at the spots were the pipes were quite close to the surface, is there a chance it could still bleed in other places in the future?

Click to expand...

That pipe work is a disgrace, you shoulde get it sorted

ianmcd said:

That pipe work is a disgrace, you shoulde get it sorted

Click to expand...

What exactly about it? Denso wrapping, where it's been hit by the chisel or something else?

Tbh, I am losing my will to live with this lot as I had multiple issues with them and just want to get it finished with them as soon as possible and forget about it. Unless - of course - you can see issues that may cause problems later on, i.e. leaks etc.

You have one pipe that is severly creased where they have bent it wrong ,and another with a severe dent in it, either could start leaking any time

ianmcd said:

You have one pipe that is severly creased where they have bent it wrong ,and another with a severe dent in it, either could start leaking any time

Click to expand...

Thanks. I had my suspicions about the dented pipe but was not aware that creases are bad too. I have requested for that to be addressed.

Denso tape is petroleum based so it's impregnated with an oil. Once the plaster is stained, it won't 'dry' out.

I have to agree with @ianmcd , that pipework is seriously rough, if that's what they have installed.

Unfortunately if that's the state of the pipework you can see, then it calls into question what's the rest of the install is like.